A frictionless pendulum is made with a bob of mass 19.7 kg. The bob is held at height = 0.934 meter above the bottom of its traj
1 answer:
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Answer: Option (b) is the correct answer.
Explanation:
The given data is as follows.
= 30 J, l = 10 cm = 0.1 m (as 1 m = 100 cm)
F = 10 N
The formula to calculate the work done is as follows.
W =
Hence, putting the given values into the above formula as follows.
W =
=
= 1 J
As the dart loses 1 joule of energy when it goes through the barrel. Therefore, the kinetic energy it has when it comes out is calculated as follows.
K.E = 30 - 1
= 29 J
Thus, we can conclude that the kinetic energy of the fired dart is 29 J.
Answer:
Focal length of the eye-lens is 2.0 cm
Explanation:
Given:
An eye-lens system which will follow converging lens (convex lens) sign conventions and knowing that lens-retina distance is the image distance.
Object distance, =
Image distance, =
cm
We have to find the focal length.
Lets say that the focal length is .
Lens Formula:
⇒
Sign-convention:
We will follow the Cartesian coordinate,placing the lens at the origin of the plane, optical center is at now as the object will be towards negative x-axis so it is negative others are on the right side of the origin so they are positive.
Using the lens formula:
⇒
⇒
⇒ <em>...as </em>
a<em>nd there is no </em>
<em> so it is zero only.</em>
⇒ cm
So the focal length is 2.0 cm with two significant figures.
Answer:
d ≈ 320000 km
Explanation:
Echoes occurs as a result of the bouncing back of sound waves as it impinges on an obstacle. Since the echo covers two distances (i.e forth and back) the distance is written as 2d.
Velocity of radio waves is taken as the speed of light =
time =2.15s
DISTANCE = VELOCITY *TIME
2d=vt
d= 322500000m
Distance to the moon is approximately 320000km